Question
i've heard you have to get the 'right' sundial for your particular latitude - how do i find one for tennessee???
p.s. is this true?

Answer
Since horizontal sundials are often mass-produced in China, Mexico or other similar places, they have to be made for just one latitude. Many are made in Birmingham England, where the latitude is around 52?deg.N, so the angle between the gnomon and the dial plate is also 52?Quite often, people bring back a sundial when they have been on holiday, so the angle may be very different. For example, a sundial made for the south of Spain will have an angle around 37 deg. and will not tell the correct time if it is set up with the dial plate horizontal in Southern England where the latitude is 51 deg. Fortunately, this can be compensated for.
I can not speak to what you need to do in Tennessee but I know you can find plenty of research on this on the internet. You are going to have to do some searching and math calculations. Have fun.Here are some good sites to start with. I did this myself once for a huge sun dial built over a pool in florida. The Gnomon was hanging from a cable in the air over the pool deck.

http://www.sundials.co.uk/setup.htm#tilted
http://en.wikipedia.org/wiki/Sundial#Garden_sundial
http://www.du.edu/~jcalvert/astro/gnomon.htm
http://en.wikipedia.org/wiki/Gnomon


Sean J Murphy, LA,ISA, LEED AP
Please check out my blogs and articles on landscape topics like this on my websites.
http://www.seanjmurphy.com
http://amenityarchitects.com